The Long-Term Evolution (LTE) is a communication technology. The Physical Downlink Control Channel (PDCCH, High Speed Physical Downlink Control Channel) is composed of a CCE and is used for bearing Downlink Control Information (DCI). The CCE is divided into public space CCE (hereinafter referred to as a public CCE) and dedicated space CCE (hereinafter referred to as a dedicated CCE), wherein the public CCE includes 0th-15th CCEs and the rest is dedicated CCE. The document of the 3rd Generation Partnership Project (3GPP), TS36.213.8.7.0, stipulates that: the DCI needing the public CCE can only adopt the CCE aggregation level L of 4 or 8, wherein when the CCE aggregation level L is 4, the start position of the CCE is respectively at the 0th, 4th, 8th or 12th CCE, and when the CCE aggregation level L is 8, the start position of the CCE is respectively at the 0th or 8th CCE; and for the DCI needing the dedicated CCE, the CCE occupied by and allocated to the DCI is determined by a Hash function which is related to subframe number, CCE sum (the number of CCEs), CCE aggregation level L, number of PDCCH candidates M(L) and the Radio Network Temporary Identity (RNTI) of a User Equipment (UE). According to the document of 3GPP TS36.212.8.7.0, the DCI includes the DCI of the format 0, format 1, format 1A, format 1B, format 1C, format 1D, format 2, format 2A, format 3 and format 3A, wherein the DCI of the format 0 (hereinafter referred to as DCI0) is used for UE uplink authorization; and the DCI of the format 1, format 1A, format 1B, format 1C, format 1D, format 2 and format 2A (hereinafter referred to as DCIx) is used for UE downlink allocation.
Only the dedicated CCE resource can be allocated to the DCI of the format 1, format 1B, format 1D, format 2 and format 2A; only the public CCE resource can be allocated to the DCI of the format 10, format 3 and format 3A; and either public CCE resource or dedicated CCE resource may be allocated to the DCI of the format 0 and format 1A. The DCI needing the public CCE resource allocated is called public DCI.
A Media Access Control (MAC) layer needs to allocate the CCE resource according to certain modes.
At present, the technology related to the allocation of the CCE resource includes: judging the CCE aggregation level L used by the public DCI and the DCI of the UE according to the wideband Channel Quality Identity (CQI) and Reference Signal Receiving Power (RSRP) information reported by the UE, or determining the CCE aggregation level L used by the UE according to the quantity of DCIx and DCI0 to be scheduled and the CCE resource. Generally, the public CCE is allocated to the public DCI by finding the public CCE resource with the minimum sequential number in the idle public CCEs. For example, a public DCI needs 4 CCE resource at the current Transmission Time Interval (TTI), and meanwhile the public CCE resource (CCE0-CCE3) in the public CCE resource (CCE0-CCE15) have been occupied. According to the above method, the public CCE resource (CCE4-CCE7) will be allocated to the public DCI. Similarly, the dedicated CCE is allocated to the DCI of the UE by finding the idle dedicated CCE resource with the minimum sequential number in the number of PDCCH candidates M(L). For example, the DCI of a UE needs 1 CCE resource at the current TTI, it is assumed that the CCEs corresponding to the number of PDCCH candidates M(L) of the UE are respectively CCE4-CCE9, and that CCE5 has been occupied. According to the above method, CCE4 will be allocated to the DCI of the UE. Therefore, the allocation of idle CCE resource in the related art may have the following problems: when CCE resource is allocated to multiple DCIs, it is possible that some DCIs are not allocated with CCE when there is idle CCE resource existing, causing waste of resource.